Cotton fiber treatment



Patented Sept. 12 1950 Jack-common, Rome, Ga., fassignor to The B. 'F. GoodrichGompany, New York; N. Y., a corpo- Lite-Drawing. nppuoation'may 22,1945.

Serial No. 595,256

' claims.

- Thisinvention relates toa method of treating cotton fibers whereby the tensile strength; elasticity and j fatigue resistance 'of such ifibers are remarkably increased. to thetreated fibers 'thereby obtainedgand to" the improved yarns, cords and fabrics preparedfrom such treated fibers.

In the production of cotton yarns, threads, cords and fabrics from cotton fibers, it has heretofore universally been thepractice to pick the cotton fibers from the cotton p'lant after -ithas reached maturity, that is, after the cotton bolls have 'opened, *to separate the "cotton fibers from the seed byginning-and then to process the fibers by operations known-as picking, carding, drawing,-'conibin'g, slubbing and roving into a "form where they may bespuninto-yarns and then twisted '-into threads and cords and/or woven into cotton fabrics. It has been proposed, however, in' the copending application of Elmer J. Cerny, "Serial No; 460,985*"fi-led Oct. '6, 1-942,-'n'o'w-Patent No. 23871058, Oct. 16,1945, to modify thispro'cedure by subjecting the cotton fibers prior'to thetim'e they are spun-into yarn toa' stressing process designed to stretch the individual-cotton fibers, whereby thetensile strength and fatigue resistanee'o'f the fibers themslvesandof the-yarnsandcordssubsequently made therefrom are greatly improved. I have now discovered that-far greater 'improvements in tensile strength and fatigue resistance of the cotton fibers and of the yarns and cordsmade therefrom-may be secured by stretching -c'otton'fibersobtained from unopened cotton bolls rather than mature open cotton bolls, preferably while thenatural constituents of the fiber including :naturalrflber moisture, are retained therein.

By the term funopened, cotton boll -I mean a cotton boll obtained from acotton plant in .that stage of its development between flowering or blossoming'and complete maturity when fibers have formed within the bolls and 'have attained substantially their maximum length and cell wall thickness but the bolls have notyet opened, this stage occurring in general in the 'last two thirds of the period betweenblossoming'and maturity, that is, from about .20 days or. so :after blossoming until opening of the bolls, which occurs .atabout 45 to;8 days after blossoming depending .upon

the"varie'ty of cotton. Preferably theicottonfllq,

bers made use of in this invention are'obtained from unopened bolls of the cotton plant during til maturity or just a few days before maturity,

for example, at 30 or 40 days after blossoming with certain-varieties of cotton which mature at to days after blossoming such as'th'evariety cif'CI-ossypium hirsutum L. Strain 4 (known'as Cokers- Super'Seven) or at a'comparable time in the development of other varieties of cotton,it being understoodthat the cotton fibers'made use of inthis invention may be obtained from any of the varieties 'of'the cotton plant (that is, plants of genus Gossypiumiof the family Malvaceae) including "the many varieties of Gossypium bar baclense such as Sea-island and Egyptian and the many varieties of Gossypium hirsutum such as New Orleans and Upland, and thelike.

In the-practice of the invention cotton fibers are obtained from cotton plants by picking the unopened bolls from the plants, crushing the bolls, separating the 'carpels and'boll partitions, from the fiber and seed contained therein and finalIyseparatingthe seed from the fiber. These operations may beefie'cteddn any desired -man-' ner by hand or by appropriate mechanical devices, it being understood that the particular method-and apparatus used in obtaining the cot-- ton fibers from immature unopened cotton bolls are not, iin themselves, apart of this invention. One convenient methodof obtaining the fibers from unopened cotton bolls consists of picking the; bolls from the plants by hand, passing the bolls throughwcrushersiand cleaners for the purpose of breaking up the unopened bells and removingthe carpels and boll partitions from the seed/and fibers,;and then passing the seed and fibers through a gin to remove the seed fromthe fibers. a

After securing the cotton fibers from unopened cotton, bolls, these mayvth'en be subjected to operations. such :as drawing andcombing, designed to arrange the, fibers in a arallel relation, sbefore proceeding;to ,the next step of stretching the 13-, hers. It.is;preferredto carry out these operations, as well as the, previous operation of removing the seeds from the fiber, as soon as possible after opening of the bolls and in a moist atmosphere. in order to prevent the removal of the natural moisture from the cotton fibers, Aqueous soluv tions of wetting agents may also be added to the. cotton. before the stretching process, if desired, but itis preferred that the cotton be in a conditionsuch that it has retained its natural moisture and the use of wetting agents is therefore 'un-:' necessary.

The stretching of the cotton fibers from unopened cotton bolls, preferably while moist with their natural moisture, may be effected by firm- 1y gripping the ends of the individual fibers and.

applying to one of the gripped ends a tension less than the breaking strength of the fibers. Preferably the tension applied is from 25 to 75% of the breaking strength of the fibers, and is applied for a short duration only, after which the tension is released and the tensioning repeated, if desired, so long as the total effect is not to break the fibers. iOne method of applying tension 'to the individual fibers is to prepare fiber bundles and mount these bundles in steel.-

grips a distance apart such that each fiber is firmly gripped, and then to suspend =-a weight from the gripped bundles. .Another method, better adapted for extensive-use, is to; passe sliver of paralleled fibers through successive pairs of rolls of equal weight and spaced apart a distance less than fiber length so that the ends of the individual cotton fibers in the'sliver are simultaneously gripped with substantially equal forces by the two' pairs of rolls, while rotating the second. .or. delivering. pair. of. .rolls.-. at a: peripheral speedgreaterf-than the-[first or entering pair of, rolls so that .tension .isapplied to the individualfibers as Ztheyare. grippedby the -rolls, and the fibersare StI'BtChGdUPOHlDflS- sage of thesliverthroughlthe rolls.

After stretching' of thefibers,..they may be dried, under tension 'ifidesired, and allowed to recover in a standard atmosphere. They are then ready to be subjectedto any of the ordinary operations in producing. cords yarns, fabrics and. other fibrous structures from .cottonfibers. For example theymay'be spun. into yarn and twisted into .tire cords which .possess tensile strength and fatigue resistance much higher than cords of similar constructionprepared from untreated mature. cotton fibers obtained from open cotton bolls and. evenhigher.than cordsof similar construction prepared, .-from..:mature. cotton ,fibers similarly obtained, :WhiCh have 'been stretched in the same way.

As. an example of theinvention further illustratingthe. advantages thereon-ta. quantity..-;of cotton .fibers were obtained. :fromncotton; plants of. the variety. known. as. CokersSuper.= Seven at 40. days. after. blossoming of :the cotton;. by picking the unopened. bolls rfromthe iplantuand aseparatingthe cotton :fibers .afrom' Ithe .'carpels.( and seeds. These 40+day;-.cotton..fibers,+which p'ossessed. an average :fibera -.length-..iof 13 were then; arranged imparallel: relatiomanduprepared into fiber bundles weighing mg.' and' consisting of. about 1500. individualzfibers. The-fiber bun dles were then mounted in steel grips, the distance:betweenthezgrips: being. 3/1'6-so that each individual. .fibervwas firmly gripped. The tensile strength of a number of these bundles was determined by :means of a Suter-tensile'testing machine. and a was found to average 13.1 'lbsiior conditioning cotton. (The fatigue resistance of 7 bundles under static conditions for 50" seconds,

and then allowing the fibers to dry under a 4 lb. load for 2 hours. The fibers were then conditioned in a standard atmosphere for 24 hours, and the tensile strength and fatigue resistance 5 then determined as before. It was found that the tensile strength of the 40-day cotton had been increased .from 13.1. .lbsr to 24.0.. lbs. by thestrje'ti' hiingi process tandithjat lthe :fatigue life had been increased from 8.1 hours to 68.5 hours.

In another example of the invention, 30-day cotton fibers from Cokers Super Seven cotton were"treated in the same manner and. it was found that..stretching of the fibers increased theten's'ilefstrength from 12.0 to 25.1 lbs. and

increased the fatigue life from 23.5 to 42.1 hours.

When fully matured cotton fibers of the same varietywere stretched in the same manner, howeverythe increase in tensile strength was only rom'142 to 16.9 lbs. and the increase in fatigue life was only from 19.6 hrs. to 26.2 hrs. It is thus. seen. that. stretching.otdmmaturefibersis far more. .eifectiveim improving tensile. strength and fatigue resistance than ..is stretching -..of maturefibers .andthat the. former yieldsfibers having. muchngreater. tensile strength and fatigue resistance. after stretching thansdoes the latter.

. Having thusldescribed nay-invention itisam' desire that it be construadbroadlw limited-only so by the spirit and scopelotuthe appended claims.

I I claim:

.1 The method which. comprises: obtainingcotton fibers from unopened bo1ls,.subJecting-Ttheindividual. fibers. to a tension. of. to" -f75.%..o-. the breaking strength of said fiber ma moistatmosphere .-.while .maintaining [the] natural moisture contentof said fibers, releasingsaid tension-drying said fibers, and allowing saidlfibers-to-recover,

2. .l'he .methodwhich comprises obtaining cot- (40 ton fibers from.unopened-bolls,Wetting said fibers withwater, subjectingthe wetted individual fibers to atension of. 254:0 35% .oftthe-breakin strength of .said fibers, releasing the. =tension, drying said fibersrandallowingsaid fiberstorecover. v .45 3.1'The method-which comprises obtainingootton fibers-from unopened bolls, arranging amultiplicity 1 .of. .said fibers.- in substantially'parallel =relation,.,subjecting. the individual fibers twhilerso arranged and whilemaintaining. the natural moisturecontent of said fibers-toatensionof 25 130.75% otthe, breaking strength of :said :fibersy-releasing said tension and. allowing said fibers ;to' recover.

.- JACK. CGMIPTON. REFEEENCESiCITED i The. following: :referencesi are: .ofi recordimythe file of this patent:

UNITEDSTATESTATENTS Number I Name. 1 (Date 1,689,443 MaeGregor, Now 30, .1928 1,846,467 .-Benjamin. ..Febp23, 1.932 1,870,039 Conrad Aug-. 2, 1932. 2,103,2l8 .Gwaltney et al-. i Dee-21,4937.

2,220,958 -.Jennings Nov. 12,1940

2,387,058 .cern Och-16, 1945,

' OTHER:-ZREEERENCES Pennsylvania. 

1. THE METHOD WHICH COMPRISES OBTAINING COTTON FIBERS FROM UNOPENED BOLLS, SUBJECTING THE INDIVIDUAL FIBERS TO A TENSION OF 25 TO 75% OF THE BREAKING STRENGTH OF SAID FIBERS IN A MOIST ATMOSPHERE WHILE MAINTAINING THE NATURAL MOISTURE CONTENT OF SAID FIBERS, RELEASING SAID TENSION, DRYING SAID FIBERS, AND ALLOWING SAID FIBERS TO RECOVER. 